The present invention relates to printing mechanisms and more particularly to a feed and support mechanism associated with a printing mechanism for printing data on sales slips or other record members associated with a data terminal device.
As part of a sales operation, a sales slip or other type of record member or document is positioned in a printing station to allow a printing mechanism to print data relating to the purchase of a merchandise item. Besides the printing of data on the sales slip, the same data is printed on other record members such as a receipt member and a journal member during the sales operation.
As part of the printing operation, a paper feed mechanism will advance the record members to a printing position prior to the printing of each line of data. Printing mechanisms which have been utilized in modern data terminal devices have included the dot matrix printer which is normally mounted on a movable carriage for movement in a horizontal direction to print lines of data on the sales slip, receipt and journal record members positioned in a side-by-side arrangement adjacent the path of movement of the carriage. Pressure rollers are used to increment the record members to a printing position, together with stop members for aligning the record members in the printing position. Each of these printer control members is normally operated by a separate solenoid actuator which contributes a large cost factor to the cost of the data terminal device. When the thickness of the inserted document varies, complicated mechanisms have also been required for controlling the positioning of the printing platen to compensate for the thickness of the record member being printed and thus enable the printing mechanism to print satisfactorily on the document regardless of its thickness. These devices are usually controlled manually by the operator and must be preset for each particular printing operation.
It is therefore a principal object of this invention to provide a mechanism which automatically feeds a sales document or other type of record member to a predetermined printing position prior to a printing operation while controlling the position of the printing platen in accordance with the thickness of the document being printed. It is a further object of this invention to provide such a mechanism which is simple in construction and therefore low in cost.